In my opinion, the prices you listed would not be enough for most people to make a living in most places and are therefore too low. The cost of living varies across the country, but there's a limit to how low it ultimately can be. And who says cake professionals should make less than everyone else?
Why charge as much as bakeries and cake professionals? Because if you don't, you're undercutting. And besides, who in their right mind doesn't want to sell his/her product for as much as they can?
If your cakes are low quality, then you would have to charge less as quality affects the price.
And as for your carved price-- there's no reason to give a price per serving for a carved cake. You might use it as part of how you privately work up a final quote, but it's not useful to help customers predict a price. Let's say you're making a 20 serving, 3d pug dog cake - are you going to sell that for $4x20= $80? Let's hope not.
Having people walk away because of your prices may be of no relevance at all. Not everyone can afford fancy cake, although most seem to feel entitled to it. They may find cheap cake lady who will do it for less. No one can compete with the cheap cake lady's prices, except other cheap cake ladies. Sometimes making cakes isn't a viable business. If all you have in your town is cheap cake ladies, then going into the cake business would probably be unwise.